Path Traversal in Cloud Foundry Bosh
CVE-2026-41009
When the director sends a long-running request (e.g. compile_package), the agent's reply JSON is consumed by AgentClient. inject_compile_log (line 332-339) reads response['value']['result']['compile_log_id'] and format_exception (line 318-325) reads exception['blobstore_id']; both pass the agent-supplied string unmodified to download_and_delete_blob(blob_id) (line 344-349), which calls @resource_manager.get_resource(blob_id) and, in an ensure block, @resource_manager.delete_resource(blob_id). Api::ResourceManager forwards the id straight to blobstore.get(id) / blobstore.delete(id). When the director is configured with the local blobstore provider, Blobstore::LocalClient#object_file_path(oid) is File.join(@blobstore_path, oid) (local_client.rb:54-56) with no normalisation, so oid = "../../jobs/director/config/director.yml" resolves outside the blobstore root. Affected versions: BOSH Director: All versions prior to v282.1.12
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:C/C:N/I:H/A:L.
EPSS exploit prediction
EPSS: 0.001 (2.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 2.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000
Affected products
Weakness classification (CWE)
References
- www.cloudfoundry.org/blog/cve-2026-41009-local-blobstore-may-allow-arbitrary-re… (Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-41009?
- CVE-2026-41009 is a medium-severity vulnerability in Cloud Foundry Bosh, classified under Path Traversal. CVSS score: 5.8/10. Published 2026-05-27.
- How severe is CVE-2026-41009?
- Medium severity. CVSS v3 base score is 5.8 out of 10.